CS227782B1 - Process for preparing p-toluenesulfonates of complex alcohols - Google Patents

Abstract

A method for preparing p-toluenesulfonates of complex alcohols of the formula where R represents 2-phenoxyethyl, 2(p-tert-butylphenoxy)ethyl or 2-benzyloxyethyl group by reacting 2-phenoxyethanol, 2(p-tert-butyl)ethanol or 2-benzyloxyethanol with p-toluenesulfonyl chloride while maintaining the alkaline reaction with an aqueous solution of alkali hydroxides until the condensation is complete, such that the reaction is carried out in an environment at a temperature of 0 to 60 UC, preferably around 25 C, and the resulting product is isolated. Substances used as quaternizing agents in the preparation of photographic sensitizers are obtained in high yield and purity.

Description

The invention relates to a process for the preparation of p-toluenesulfonates of the general formula

wherein R represents 2-phenoxyethyl-, 2- (p-tert-butylphenoxy) ethyl- and 2-benzyloxyethyl, used as important quaternizing agents in the preparation of photographic sensitizers. p-Toluenesulfoesters of simple alcohols are prepared by, for example, admitting an aqueous solution of alkali hydroxides to a suspension of p-toluenesulfochloride in an excess of esterified alcohol (e.g., Organic. Synth. Goll. Vol. I, 145), or more complex alcohols by adding p-toluenesulfochloride to a solution of alcohol in excess pyridine (US Pat. 2496842, CA 68, 5742 (1950)). Isolation of pure substances is relatively complex in both cases, and there is no need to laboriously regenerate large amounts of the starting alcohol or pyridine used. The products must be purified by distillation under vacuum or by recrystallization from technical solvents.

It has also been found that the p-toluenesulphonates of the above composition can be prepared in high yield in a simple manner, and the products need not be purified further. To this end, an aqueous solution of an alkali hydroxide, preferably sodium hydroxide, is added dropwise to the suspension or solution of the alcohol and p-toluenesulfochloride in acetone until a permanent reaction on phenolphthalein paper and the disappearance of the free p-toluenesulfochloride disappears. In order to obtain a pure product, the ratio of the reactants is not important and the highest yield can be achieved at about 10% excess

3 227782 p-toluenesulfochloride. A ratio other than optimal results in a reduced yield or unreacted component discharge into the wastewater. An essential condition is the use of acetone as the reaction medium. Its amount is not critical and can vary within wide limits. At low amounts, however, the reaction mixture is not well mixable and at high levels the product is hardly isolatable and losses occur. The reaction temperature may be from 0 ° C up to the boiling point of acetone, but optimally lies at 25 when the reaction is fast enough and there is minimal decomposition of p-toluenesulfochloride ^U or the ester formed.

The examples below illustrate embodiments of the invention. Example 1

To a suspension of 138 parts wt. phenoxyethanol and 210 parts wt. p-toluenesulfochloride in 200 parts by volume of acetone is added dropwise with rapid stirring 130 parts by volume of aqueous sodium hydroxide solution c (NaOH) = 10 mol / l, maintaining the temperature of 25 ° C, and then stirred for 1 hour with optional sodium hydroxide solution. that the reaction is still alkaline to the phenolphthalein indicator. 170 volumes of 50% ethanol are now added to the crystalline suspension formed, cooled to 5 °, suction filtered, washed with 170 volumes of 50% ethanol and finally with excess water. After air drying, 274 parts game are obtained. of pure crystalline phenoxyethyl p-toluenesulfonate, m.p. 75 DEG C. Example 2

The procedure was the same as in Example 1, but using 194 parts by weight instead of phenoxyethanol. 322 parts by weight of 4-tert-butylphenoxyethanol are obtained. 82 DEG-84 DEG C. 4-tert-butylphenoxyethyl p-toluenesulfonate.

Example 3

Using the same procedure as in Example 1, but using 153 parts by weight. of benzyloxyethanol, instead of phenoxyethanol, 190 parts by weight of benzyloxyethanol are obtained. m.p. 44-46 ° C; benzyloxyethyl p-toluenesulfonate;

Claims (2)

SUBJECT OF THE INVENTION A process for preparing p-toluenesulfonates of complex alcohols of formula Wherein R is 2-phenoxyethyl, 2 (p-tert-butylphenoxy) ethyl or 2-benzyloxyetylskupinu reaction of 2-phenoxyethanol, 2- (p-t-butyl) ethanol and 2-benzyloxyethanol with p-toluenesulfonyl chloride, maintaining the reaction alkaline with aqueous alkali hydroxide solution until completion of the condensation, characterized in that the reaction is performed in place of the i ^ ^e pr ^{At a} temperature of 0 to 60 ° C, preferably about 25 ° 0, and the product formed is isolated.